scholarly journals Spectroscopic Understanding of SnO2 and WO3 Metal Oxide Surfaces with Advanced Synchrotron Based; XPS-UPS and Near Ambient Pressure (NAP) XPS Surface Sensitive Techniques for Gas Sensor Applications under Operational Conditions

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4737 ◽  
Author(s):  
Engin Ciftyürek ◽  
Břetislav Šmíd ◽  
Zheshen Li ◽  
Vladimír Matolín ◽  
Klaus Schierbaum

The most promising and utilized chemical sensing materials, WO3 and SnO2 were characterized by means advanced synchrotron based XPS, UPS, NAP-XPS techniques. The complementary electrical resistance and sensor testing experiments were also completed. A comparison and evaluation of some of the prominent and newly employed spectroscopic characterization techniques for chemical sensors were provided. The chemical nature and oxidation state of the WO3 and SnO2 thin films were explored at different depths from imminent surface to a maximum of 1.5 nm depth from the surface with non-destructive depth profiling. The adsorption and amount of chemisorbed oxygen species were precisely analyzed and quantified as a function of temperature between 25–400 °C under realistic operating conditions for chemical sensors employing 1–5 mbar pressures of oxygen (O2) and carbon monoxide (CO). The effect of realistic CO and O2 gas pressures on adsorbed water (H2O), OH− groups and chemisorbed oxygen species ( O 2 ( a d s ) − ,   O ( a d s ) ,   − O 2 ( a d s ) 2 − ) and chemical stability of metal oxide surfaces were evaluated and quantified.

2018 ◽  
Vol 20 (18) ◽  
pp. 12678-12687 ◽  
Author(s):  
Getachew G. Kebede ◽  
Pavlin D. Mitev ◽  
Wim J. Briels ◽  
Kersti Hermansson

The OH vibrational signatures of water and hydroxide species on MgO(001) and CaO(001) are found to correlate strongly with the electric field generated by the surrounding surface structure over each OH oscillator. The result is two different parabolas, one for OH− species, one for H2O.


2006 ◽  
Vol 110 (15) ◽  
pp. 7835-7844 ◽  
Author(s):  
Erwin Portuondo-Campa ◽  
Andreas Tortschanoff ◽  
Frank van Mourik ◽  
Jacques-Edouard Moser ◽  
Andreas Kornherr ◽  
...  

2013 ◽  
Vol 53 (21) ◽  
pp. 81-94 ◽  
Author(s):  
P. M. Murphy ◽  
C. Boxall ◽  
R. J. Taylor ◽  
D. A. Woodhead

2017 ◽  
Vol 8 (4) ◽  
pp. 3070-3079 ◽  
Author(s):  
Julien Warnan ◽  
Janina Willkomm ◽  
Jamues N. Ng ◽  
Robert Godin ◽  
Sebastian Prantl ◽  
...  

A series of diketopyrrolopyrrole (DPP) dyes with a terminal phosphonic acid group for attachment to metal oxide surfaces were synthesised and the effect of side chain modification on their properties investigated.


Author(s):  
H. Terryn ◽  
O. Blajev ◽  
S. Van Gils ◽  
J. van den Brand ◽  
A. Ithurbide ◽  
...  

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